The objective of this project is to create hearing and at least limited speech comprehension in totally deaf persons by electrical stimulation of the auditory nerve. Deaf human volunteers receive multi-electrode implants within the inner ear. Basic psychophysical stimulation experiments measure the range of auditory percepts for each electrode and this data is then used as design criteria for the development of computer-generated "speech processors" or acoustic feature detectors. The processors so developed are used to code speech sounds for electrical stimulation. Concomitant with this human research are animal experiments verifying the safety, tissue tolerance, and other features helpful and necessary for the human research.